Jens Kreuz

Safety, feasibility, and diagnostic value of cardiac magnetic resonance imaging in patients with cardiac pacemakers and implantable cardioverters/ defibrillators at 1.5 T

BACKGROUND Recent studies suggest that magnetic resonance (MR) imaging of the brain and spine may safely be performed in patients with pacemakers (PMs) and implantable cardioverter/defibrillators (ICDs), when taking adequate precautions. The aim of this study was to investigate safety, feasibility, and diagnostic value (DV) of MR imaging in cardiac applications (cardiac MR [CMR]) in patients with PMs and ICDs for the first time. METHODS Thirty-two PM/ICD patients with a clinical need for CMR were examined. The specific absorption rate was limited to 1.5 W/kg. Devices were reprogrammed pre-CMR to minimize interference with the electromagnetic fields. Devices were interrogated pre-CMR and post-CMR and after 3 months. Troponin I levels were measured pre-CMR and post-CMR; image quality (IQ) and DV of CMR were assessed. RESULTS All devices could be reprogrammed normally post-CMR. No significant changes of pacing capture threshold, lead impedance, and troponin I were observed. Image quality in patients with right-sided devices (RSD) was better compared with that in patients with left-sided devices (LSD) (P < .05), and less myocardial segments were affected by device-related artefacts (P < .05). Diagnostic value was rated as sufficiently high, allowing for diagnosis, or better in 12 (100%) of 12 patients with RSD, and only in 7 (35%) of 20 patients with LSD. CONCLUSIONS Cardiac MR may be performed safely when limiting specific absorption rate, appropriately monitoring patients, and following device reprogramming. Cardiac MR delivers good IQ and DV in patients with RSD. Cardiac MR in patients with RSD may therefore be performed with an acceptable risk/benefit ratio, whereas the risk/benefit ratio is rather unfavorable in patients with LSD.

Strategy for safe performance of magnetic resonance imaging on a patient with implantable cardioverter defibrillator.

Clinically indicated magnetic resonance imaging (MRI) of the brain was safely performed at 1.5 T on a patient with an implantable cardioverter defibrillator (ICD). The ICD was reprogrammed to detection only, and imaging hardware and protocols were modified to minimize radiofrequency power deposition to the ICD system. The integrity of the ICD system was verified immediately post‐MRI and after 6 weeks, including an ICD test with induction of ventricular fibrillation. This case demonstrates that in exceptional circumstances, in carefully selected patients, and using special precautions, an MRI exam of the brain may be possible in patients with ICDs.

Independent predictors of mortality in patients with advanced heart failure treated by cardiac resynchronization therapy.

AIMS The current study includes all consecutive patients with advanced heart failure and cardiac resynchronization therapy (CRT) with an implantable cardioverter defibrillator (ICD) over a 10-year period in a tertiary referral centre. It aims at identifying independent risk factors for mortality during CRT-defibrillator (CRT-D) treatment. METHODS AND RESULTS This study includes 239 consecutive patients who had undergone implantation of a CRT-D system (ejection fraction 25.9 ± 8%; 139 patients with ischaemic, 100 patients with non-ischaemic cardiomyopathy). Enrolment took place between 2001 and 2010, resulting in a median follow-up of 43 ± 30 months. During follow-up, 59 patients (25%) died. An impaired baseline kidney function [hazard ratio (HR) 1.98; 95% confidence interval (CI) 1.7-3; P< 0.0001], appropriate ICD therapy during follow-up (HR 2.1; CI 1.1-3.4; P= 0.001), lack of beta-blocker therapy (HR 2.3; CI 1.6-3.8; P= 0.004), and intake of amiodarone (HR 2; CI 1.8-4.1; P< 0.0001) were identified as predictors of overall mortality. CONCLUSION This study demonstrates the benefit of beta-blocker therapy also in patients on long-term CRT-D treatment. It confirms the prognostic significance of impaired renal function and the occurrence of appropriate ICD therapies also in CRT-D patients. It argues for an intensified follow-up regimen and adjustment of heart failure treatment whenever these prognostic markers are identified in a patient treated with CRT-D.

An impaired renal function and advanced heart failure represent independent predictors of the incidence of malignant ventricular arrhythmias in patients with an implantable cardioverter/defibrillator for primary prevention

AIMS Malignant ventricular arrhythmias and inappropriate therapies represent unsolved problems in patients with implantable cardioverter/defibrillator (ICD) for primary prevention. This study focuses on the incidence of such therapies and thereby seeks to identify new predictors of adverse events to enhance risk stratification. METHODS AND RESULTS Ninety-four consecutive patients with mild-to-moderate heart failure (NYHA II-III) and depressed left ventricular function (≤35%) were followed for 34 ± 20 months. Two hundred and ninety-one malignant ventricular arrhythmias were documented in 51 patients (54%). Eighteen patients (19%) received inappropriate ICD therapies (e.g. atrial fibrillation, sinus tachycardia, etc.). Patients with malignant arrhythmia (1.34 ± 0.44 vs. 1.16 ± 0.4 mg/dL, P = 0.017) and patients suffering from inappropriate ICD therapies (1.54 ± 0.48 vs. 1.2 ± 0.38 mg/dL; P = 0.007) revealed a significantly worse renal function before ICD implantation than participants without any therapy. An increased serum creatinine at baseline (2 vs. 1 mg/dL; odds ratio (OR) 3.96; P = 0.02; 95% CI: 1.2-13.04) and NHYA class III compared with II (OR: 2.96; P = 0.02; 95% CI: 1.16-7.48) represent strong and independent predictors for the occurrence of ventricular arrhythmias. Moreover, an impaired renal function is identified as an independent risk factor for inappropriate therapies (OR: 5.6; P = 0.004; 95% CI: 1.72-18.22). CONCLUSION An impaired renal function and advanced heart failure before ICD implantation for primary prevention are identified as independent predictors for the incidence of appropriate ICD interventions. With regard to current guidelines and economical aspects, patients suffering from an impaired renal function or advanced heart failure seem to benefit most from ICD therapy.

Pulmonary Arterial Hypertension in Patients with Sarcoidosis: The Pulsar Single Center Experience

Sarcoidosis is a systemic granulomatous disease with unknown etiology. Lungs and lymph nodes are commonly affected. Also, cases of pulmonary hypertension (PH) and pulmonary arterial hypertension (PAH) are described. However, the exact prevalence of PAH in patients with sarcoidosis is unclear. A 111 patients with proven sarcoidosis were recruited from January 2010 to October 2010. All patients were studied prospectively by transthoracic echocardiography (TTE) for the presence of PH. In assumed PH, a right heart catheterization (RHC) followed if there were no other reasons for PH. In 23 of the 111 patients (21%) PH was assumed in TTE. Three patients presented with severe mitral insufficiency III° and IV°, in eight patients PH was supposed to be caused by chronic heart failure or relevant diastolic dysfunction > II°, two patients declined undergoing RHC. Of the ten patients investigated with RHC, four showed a precapillary pulmonary arterial hypertension and in one patient a postcapillary hypertension was diagnosed. All four patients with precapillary PH had a radiologic stage III and IV. In three of the four patients a significantly reduced transfer factor for carbon monoxide (TLCO) <50% was found. All patients with precapillary PH had a chronic course of sarcoidosis lasting ≥13 years. This is the first study which prospectively investigated a large cohort of patients with sarcoidosis for the prevalence of PH and PAH. The prevalence of precapillary PH was found to be at least 3.6% (4/111) and therefore exceeds the prevalence of PAH in the normal population by far. A chronic and progressive lung involvement due to sarcoidosis seems to be the most evident risk factor for developing a sarcoidosis PH.

Modern noninvasive risk stratification in primary prevention of sudden cardiac death.

ObjectiveSince the publication of MADIT II and SCD-HeFT, an implantable cardioverter defibrillator (ICD) for primary prevention represents an established, guideline-implemented therapeutic strategy. Facing such an enormous amount of potential ICD recipients, the identification of an effective risk stratification remains crucial.MethodsThis article reviews the tools of noninvasive risk stratification which are currently used and defines an optimal test configuration. This analysis focuses on the capacity of the tests regarding to the negative predictive value to reduce unneeded devices.ResultsPresently, no marker exists in terms of risk stratification which qualifies itself as gold standard. However, encouraging results can be stated for microvolt T-wave alternans (mTWA) providing a high negative predictive value. An increased QT variability (QTv) and an impaired deceleration capacity are associated with an excellent positive predictive value. Currently, only mTWA and QTv seem to be suitable in ischemic and non-ischemic disease, but available data, especially in non-ischemic patients, are too small to provide clear recommendations.ConclusionThe most hopeful tools at hand in modern noninvasive risk evaluation of sudden cardiac death in primary prevention seem to be mTWA and QTv. These noninvasive methods provide the best negative predictive or positive predictive value of all known parameters, while a higher rate of complete coronary revascularizations in acute coronary syndromes might also reduce the number of fatal arrhythmic events and therefore complicate the invention of an ideal risk marker.

Significance of Wedensky Modulation testing in the evaluation of non-invasive risk stratification for ventricular tachyarrhythmia in patients with coronary artery disease and implantable cardioverter-defibrillator

Objective: Evaluation of the significance of the Wedensky Modulation (WM) examination for ventricular tachyarrhythmias (VT) in patients with coronary artery disease and implantable cardioverter-defibrillator therapy (ICD). Design: Prospective, single-centre study conducted from 2004 to 2006. Setting: University of Bonn, Department of Medicine – Cardiology, Bonn, Germany. Patients: 37 consecutive patients with coronary artery disease receiving an ICD for primary or secondary prevention. Main outcome measures: Correlation of a positive WM-Index (WMI) with established non-invasive Holter parameter, the occurrence of VT after ICD implantation with regard to primary or secondary prevention, and inducibility of VT during electrophysiological (EP) studies. Results: The WMI was positive in 15 patients (67 (SD 8) years, 31% (SD 12%) EF) and showed significant correlation with heart rate variability (standard deviation of normal to normal intervals (SDNN): 143 (SD 80) ms vs 102 (SD 29) ms, p = 0.04, r = 0.45; total power (TP). 11 885 (SD 19 674) ms2 vs 2229 (SD 1779) ms2, p = 0.03, r = 0.384; very low frequency component (VLF): 2777 (SD 3039) ms2 vs 1184 (SD 565) ms2, p = 0.03; low frequency component (LF): 2955 (SD 5734) ms2 vs 468 (SD 725) ms2, p = 0.05, r = 0.375; high frequency component (HF): 4885 (SD 9939) ms2 vs 382 (SD 609) ms2, p = 0.05, r = 0.315) and turbulence (turbulence onset (TO): −0.002 (SD 0.008) vs +0.005 (SD 0.01), p = 0.05, r = 0.301; turbulence slope (TS): 3.4 (SD 3.1) vs 1.7 (SD 1.5), p = 0.04, r = 0.419). The positive predictive value of the WMI considering the inducibility of VT during EP testing was 100%. Those patients who received an ICD for primary prevention showed a higher WMI (p = 0.049) than the secondary prevention group. With respect to the occurrence of adequate VT episodes, a negative WM test result demonstrated a negative predictive value of 95%. Conclusion: The data presented show that the WM-Index predicts VT inducibility during EP testing and indicates a high negative predictive value regarding the occurrence of VT.

Superiority of Gold versus Platinum Irrigated Tip Catheter Ablation of the Pulmonary Veins and the Cavotricuspid Isthmus: A Randomized Study Comparing Tip Temperatures and Cooling Flow Requirements

Gold versus Platinum Irrigated Tip Ablation Catheters. Introduction: In order to optimize power delivery into the myocardium during radiofrequency ablation (RFA) without overheating the electrode tip, active cooling of the tip electrode as well as electrode tips made of gold have evolved. Recently, an externally irrigated gold tip electrode ablation catheter has been developed to combine the advantages of these 2 technologies. We sought to investigate the procedural parameters tip temperature, delivered power and cooling flow requirements of the irrigated gold tip catheter in comparison to the conventional irrigated platinum iridium (Pt) tip catheter in pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) ablation.

Impact of pulmonary vein isolation on obstructive sleep apnea in patients with atrial fibrillation

BACKGROUND Obstructive sleep apnea (OSA) has been identified as associated with the onset and propagation of atrial fibrillation (AF) and predicts recurrences of AF after pulmonary vein isolation (PVI). Vice versa, it has never been investigated whether PVI influences OSA. However, it has been controversial whether a restored atrial function can affect the course of OSA. There-fore, we have assessed whether PVI procedure modulates the prevalence and severity of OSA. METHODS AND RESULTS We included 23 individuals with AF that were assigned to undergo PVI into this study. Patients were 65 ± 7 years old, obese (BMI 29.9 ± 5.4 kg/m²), white (100%) and had a normal left ventricular function (LVEF 64 ± 9%). Polygraphic assessment was carried out before and 6 months after PVI. The prevalence of OSA, defined as an apnea-hypopnea index (AHI) ≥ 5 per hour of sleep, was 74% before PVI compared to 70% 6 months after the procedure (p > 0.05). Severity of OSA did not differ (AHI before vs. after: 18 ± 18/h vs. 15 ± 17/h, p > 0.05) as well as further polygraphic parameters did not differ before and after the procedure. CONCLUSIONS Prevalence and severity of OSA are not affected by PVI in patients suffering from AF.

Neue Aspekte der kardialen Resynchronisationstherapie (CRT-D)

Ziel dieses Übersichtsartikels ist die Vorstellung der drei maßgeblichen Studien zur Evaluation der Relevanz einer kardialen Resynchronisationstherapie mit implantierbarem Cardioverter/Defibrillator (CRT-D) im Hinblick auf die Morbidität und Mortalität von Herzinsuffizienzpatienten mit hochgradig eingeschränkter linksventrikulärer Pumpfunktion, verbreitertem QRS-Komplex und leichten bis moderaten Herzinsuffizienzsymptomen im NYHA Stadium I/II bzw II/III. Die REVERSE- und MADIT-CRT-Studie widmeten sich hierbei Patienten im Stadium NYHA I/II, wohingegen in die RAFT-Studie Patienten im Stadium II/III eingeschlossen wurden. Zusammenfassend lässt sich konstatieren, dass eine CRT-D, insbesondere im Hinblick auf eine Verminderung der Hospitalisierung aufgrund einer Herzinsuffizienzproblematik, im NYHA-Stadium II Vorteile im Vergleich zu einer reinen ICD-Therapie zeigte. Ein signifikanter Mortalitätsvorteil konnte im NYHA-Stadium I und II jedoch in keiner Studie gezeigt werden. Die 2010 novellierte ESC-Empfehlung zur Device-Therapie bei Patienten mit chronischer Herzinsuffizienz berücksichtigt die Ergebnisse der o. g. Studien (Empfehlungsgrad I). Demzufolge wird die CRT-D um Patienten mit milder Herzinsuffizienz erweitert, um ein Voranschreiten der Erkrankung zu verhindern. Im Falle des Vorliegens von persistierendem Vorhofflimmern oder einer Indikation zur antibradykarden Stimulation liegen für Patienten mit verbreitertem QRS-Komplex keine randomisierten Daten vor. Prinzipiell sollte bei diesem Patientenkollektiv das Ziel in einer hohen biventrikulären Stimulationsrate ≥95% liegen.